Rotary pump



May 31, 1932. A -PETERSQN 1,860,817

ROTARY PUMP.

Filed Oct. 5, 1928 @fluff/M Patented May 31, 1932 UNITED STATES PATENT OFFICE .ARVID PETERSON, F TRENTON, NEW JERSEY, ASSIGNOR TO DE LAVAL STEAM TURBINE COMPANY, OF TRENTON, NEW JERSEY, A CORPORATION 0F NEW JERSEY ROTARY PUMP Application led October 8, 1928. Serial No. 309,909. I

This invention relates to a rotary pump and more particularly to balancing means therefor.

Heretofore it has been customary to balance the rotor of a centrifugal impeller against end thrust by providing cooperating stationary and fixed rings through which liquid from the discharge is arranged to flow to maintain a hydraulic balance of the rotating parts. It is found that where rings have heretofore been provided for this purpose wear occurs and tends to provide so large a clearance as to cause the balancing means to fail to properly take up the thrust of the rotor.

It is accordingly the primary object of the present invention to provide a balancing means of the character described which is adjustable to provide for a taking up of the parts when Wear occ-urs. It is a further object to-provide means of this character which may be readily assembled and on which indication is clearly given of the clearance provided. Other more detailed objects of the invention will be apparent from the following description.

The invention is described in connection with a steam turbine driven centrifugal pump which is more fully described in the application of Rudolph Birmann, Serial No. 312,767, filed October 16, 1928, relating to improvements in controlling means for turbines, and reference is made to that application for a more complete and detailed description of the mechanism as a whole.

In the drawings:

Fig. 1 is a longitudinal vertical section through the main shaft of a centrifugal pump.

Fig. 2 is an elevation showing details of the adjustable leak-ofi' ring.

The mechanismv in which the present invention is incorporated comprises acasing designated generally by numeral 2, in which a shaft 4 is mounted in suitable bearings 6 and 8 carried by the castingl which forms the bottom of the casing. On the right hand end of shaft 4, as viewed in Fig. 1, is mounted a turbine wheel 10 which is driven by steam passing through a suitable nozzle (not surrounded by packing 18 held in place by a suitable gland to prevent escape of liquid. The impeller wheel is provided with suit- `able blades forming passageways 20 which impart to liquid entering through an inlet 22 a high rotational velocity, the liquid being discharged through passages 24 in a diffusing ring 25 into a volute 26 from which it is discharged through a suitable tube for convertlngd-the high velocity head into pressure -Diifusing ring `25 is held stationary in the casing by any suitable means and is provided With an inwardly directed xed balancing disk 28 provided with a plane face contacting with a similar opposed plane face of a balancing ring 30 carried by the impeller wheel.

The opposite face of balancing ring 30 is opposed to a leak off ring 32 which, as shown in the drawings, is threaded within the stationary diffusing ring 25. Leak olf ring 32 is provided with an annular flange 34 through which slots 36 are formed. A pin 38 threaded into a stationary part of the casing is adapted to pass through a suitable slot 36 to hold the ring against movement.

During operation of the impeller, the intake suction and steam pressure tend to move the impeller wheel, shaft and turbine wheel to the left, as viewed in Fig. 1. As will be noted from this figure, the discharge of the impeller communicates with the opposed plane faces of disc 28 and ring 30, so that these faces will be forced apart by the discharge pressure. As disc 28 and ring 3() are thus forced apart, the space between rings 30 and 32 is reduced thus cutting down the flow to the suction through passages 40 and 42 and producing a building up of pressure to the right of ring 30. An equilibrium is reached when the pressure at the right of ring 30 and the end thrust are balanced by the pressure at the left of ring 30. An equilibrium position is thus attalned, the distances between rings 28 and.30 and 30 and 32 respectively becoming so related as to maintain a continuous flow of liquid therethrough, thus maintaining ring 30 out of contact with rings 28 and 32 and providing a thrust bearing for the impeller and its associated rotating parts.

While bearing 6 is arranged to cooperate with rings 7 to reduce excessive endwise movement of shaft 4, the clearance between the bearing 6 and rings 7 is made greater than the movement of the shaft as the ring 30 moves between rings 28 and 32, so that bearing 6 does not act as a thrust'bearing, the thrust being taken up entirely by the rin y removing pin 38 from the slot in ring 32, ring 32 may be adjusted in an axial direction by rotating the same, thus screwing the same into or out of the fixed diffusing ring. This adjustable construction of ring 32 provides for ready and exact initial assembling and adjustment for wear. In order to obtain proper clearance in assembling, ring 32 may be-screwed inwardly until the three rings are brought into engagement. By then'backing off ring 32 by turning it a distance corresponding to a definite number of notches 36 and inserting pin 38, the proper clearance is obtained. The notches are so arranged that a turn of the ring through an angle corresponding to that between adjacent notches corresponds to a definite axial movement of the ring, so that the clearance may be readily determined.

What I claim and desire to protect by Letters Patent is:

1. A rotary pump including a casing, a shaft, a pump rotor carried by the shaft with# in the casing, a central intake passage, an annular discharge passage, passages in the rotor extending from the intake passage to the discharge passage, a turbine rotor mounted on the shaft, the thrust incidental to the operation of both the pump and turbine rotors tending to move the shaft towards the intake passage, and means for balancing said combined thrust including a xed ring member carried by the casing on the side of the pump rotor opposite the intake passage and providing a stationary face facing away from the intake passage, a rotating ring mounted to rotate with the rotor having a face adjacent the face of said fixed ring, the clearance between them communicating with the discharge, and a second annular ring havin 4a face adjacent a face on the opposite si e of the rotating ring, the clearance between the last named faces forming a leakoff passage, the second annular ring being threaded. in the casing, the threads having a radius greater than the leak olf passage,

whereby its rotation produces axial movement thereof thereby adjusting the sum of the clearances between the airs of faces, liquid from the discharge beln adapted to pass radially outwardly from t e discharge passage between the first pair of faces, around the periphery of the rotating ring, and thence through the leak-off assage.

2. A rotary pump inclu ingl a casing, a rotor mounted in the casin a central intake passage, an annular disc arge passage, a rotating ring removably carried by the rotor to rotate therewith, a stationary rin extending inwardl between the rotor and t e rotating ring an having an inner radius less than the outer radii of t e rotor and rotating ring,

said stationar ring having an integral exj tension exten ing axially over the periphery of the .rotating ring, the minimum internal radius of the extension being greater than the outer radius of the rotatin ring, and a second stationary ring threaded; to the extension, the adjacent faces of the first stationary ring and the rotating ring being in commumcation with the discharge, and the adjacent faces of the second of said stationary rings and the rotating ring forming a leak off passage, wherebyrotaryr adjustment of the second stationary. ring 1n the extension produces axial movementl thereof to adjust the sum of the clearances between the rotating ring and the stationa rings.

Inf testimony of w ich invention, I have hereunto set my hand, at yTrenton, New Jersey, on this 28th day of/September, 1928.l

` ARVID PETERSON.

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